Optical system for spectral apparatus



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OPTICAL SYSTEM FOR SPECTRAL APPARATUS 4 Filed DBC. .27, 1940 f; i i I: HA i? if T1 .s

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UNITED STATES PATENT'oFFlc'E mam l. l

OPTICAL snm Gerau-s nanna, rn, Germany; mies in the custodian AlienProperty l Application December 27, 1949, SerialNo. 371,929

In Germany December l1, 1939 9 Claims. (Ci. 98-10 Application has beenmed in Germany, Detwo Jaws c, and the other a lens d and a slit encember 11, 1939. formed by two Jaws e. The lenses b and d are oi Theinvention relates to an optical system ior spectral. apparatuscomprising two lens system, a dispersion system lying between said twolens systems and an autocollimation mirror which, for the purpose oi'changing over in the use oi the apparatus from the single passage oilight to autocollimation, can be brought from one o! two positions intothe other, i. e., into the working position, where it lies between thesaid two lens systems and where it reiiects the light which A has passedthrough the one lens system and through the dispersion system in such amanner that the light is made to pasa through said two systemsasecondtime.

According to the invention an optical system as described is providedwith a reflector system denning the path of the rays, the reilectorsystem causing the light in either oi the two applications ot theapparatus to be conducted to one and the same destination, i. e., eitherto one and the same light-emerging slit, or to one and the samephotographic layer, said renector system containing reflectors in fixedposition acting upon the full pencil oi light conducted to them. andalso a rei'iector of the light-separating type. either in a iixedposition or so disposed that it can be swung in or out oi' the way otthe light rays. I

The working position the autocollimating reiiector is recommended tooccupy relative to the other parts of the optical system is such that.the reiiecting surface of said reflector is about perpendicular to theaxial light-ray.

A suitable optical system according to the invention is obtained ifprovision is made for two adjacent light-entering slits to be separatelyexposed to light and one o! which is tobe used when the apparatus isemployed for the single passage of light, while the other is intendedtohe used when the apparatus is employed ior autocollimation the positionof the two lightentering slits relative to the elements of the opticalsystem being such that the light emitted from the one-slit is conveyedto the one and the light emitted from the other slit to the other oi thetwo lens systems.

In Figs. 1 to 3 oi the annexed drawing three diagrammatic illustrationsare given oi optical systems oija spectral apparatus according to theinvention. l

To the prism a o! the optical system shown in Fig. 1 two'collimators arecoordinated one diilerent focal lengths. The slit c is the lightenteringslit to which a light-source t is co-ordis nated. A reiiector c servesfor deviating the optic axis of the collimator Upon by 90, while areflector h serves to again deviate the deviated part oi the optic axisuntil, after a further deviation through Prism a said part oi the opticaxis' 10 coincides with the axis ot the collimator d. et. Those twoparts of the optic axis containing the slit cs, and slit eo,respectively, intersect each other at a point A at right angles. Theletter i designates a swing-in and out reiiector which is so disposedthat, when swung-in, it occupies the position indicated in the drawingby the full lines i. e., where its reflecting suriace io is parallel tothat o! the reflector g and where it contains said intersecting point A.'Ihe renector i is bounded by the plane containing the optic axes oi thelenses b and d, so that it can reiiect only light rays lying to one sideci said plane. A second swing-in and out reiiector k when swung-inoccupies the position indicated in the drawing by the full lines andwhere its reiiecting surface ka is at right angles to the optic axis.

When the reflectors i and k are in swung-out position the rays emanatingfrom light-source l run in the 'direction oi' the fully drawn arrows forsingle passage of light, while. after vinterposing these reflectors intothe light-path the rays run as indicated by the broken arrows showingthat :shel apparatus works on the autocollimation prin` Theconstructional example according to Fig. 2 diilers from Fis. l merely bythe lens b occupying another position which is determined by theequality of the focal lengths oi' the lenses b and d.

The constructional example according to Fig. 8 diiiers from that shownin Fig. l by the focal lengths of lenses b and d being equal to one an'other without their position being changed relative to prism a. Thisnecessitates the provision oi a second light-entering slit la which isformed by the two Jaws l. `To this slit lo a light-source m iscoordinated. That part oi' the optic axis containing the slit ltis sodeviated by a reflector n whose renectingsurface is parallel in that ofthe renector a, that after its deviation it coincides with that part ofthe optic axis containing the light-emanating slit eo. The renector n isbounded by the plane containing the optic axes of the lenses b and d. sothat it can reiiect only oi.' which has a lens b and a slit es formed by5s light rays lying to one side of said plane. 'I'he 2 v :,aosn'm lswing-in and out reflector i has been dispensed with.

If the apparatus is intended to be used for single passage oi' light.the light-source f is required to be active and the renector Icswung-out, whereas if the autocollimation principle is to be employedthe reflector k must be swung-in. with the lightsource m being active.

I claim:

1. In an optical system for spectral apparatus which are to be used forsingle passages ot light as well as for autocollimationl two lenssystems adapted to produce of a light spot which coincides with thefocal point of one oi said lens systems an image coinciding with thefocal point of the other lens system. a dispersing system between saidtwo lens systems. a mirror disposed for swinging itin the way and out oi the way of the light rays emerging from said light spot, said mirrorlying in its position for use, which it occupies when the apparatus isto be used for autocollimation, between said dispersing system and oneo! said two lens systems and, by reflection. causing the lighttransmitted by the other of said two lens systems and said dispersingsystem once more to traverse said dispersing system and said other lenssystem.

and a system of mirrors for regulating the ways which the light rays insaid both cases of use of the apparatus take from said light spot to theplace of ,said image. the position of said mirror system relative to theother members of the op tical system and to said light spot and to theplace of said image being such that said ways oi' light rays cross eachother. one mirror of said mirror system serving for rei'iecting lightrays only when the apparatus is to be used for autocollimation, said onemirror being adapted to influence only part of the light rays and lyingat the place of crossing of said ways of light rays.

2. In an optical system for spectral apparatus which are to be used forsingle passage of light as well as for autocollimation. two lens systemsadapted to produce of a light spot which coincides with the focal pointof one of said lens systems an image coinciding with the focal point ofthe other lens system. a dispersing system between said two lenssystems, a mirror disposed ior swinging it in the way and out of the wayof the light rays emerging from said light spot. said mirror lying inits position for use, which it occupies when the apparatus is to be usedfor autocollimation. between said dispersing system and one o! said twolens systems and perpendicularly to the axis of the pencil of light raystransmitted by the other of said two lens systems and said dispersingsystem, and thus causing the light ray coinciding with said axis to berenected in itself. and a system of mirrors for regulating the wayswhich the light rays in said both cases of use of the apparatus takefrom said light spot to the place of said image. the position of saidmirrors relative to the other members of the optical system and to saidlight spot and to the Place of said image being such that said ways oflight rays cross each other, one mirror oi' said mirror system servingfor reilecting light rays only when the apparatus is to be used forautocollimation. said one mirror being adapted to influence only part ofthe light rays and lying at the place of crossing of said ways of lightrays.

3. In an optical system according to claim l, two slits for lightentrance adapted to receive light when the apparatus is to be used forsingle light passage or for autocollimation, respectively, one

o! said two slits lying in the focal plane of one of said two lenssystems and the other slit lying in the focal plane of the other lemsystem.

GERHARD HANSEN.

